Method for Vertically Extruding a Concrete Element, Device for Producing a Concrete Element, and Wind Turbine Generator Tower Produced by This Method

ABSTRACT

Device for producing an elongated concrete element extending in the vertical direction, for example a tower of a wind turbine generator system, comprising an inner casing and an outer casing, the inner casing and the outer casing being configured in such a way that between the inner casing and the outer casing there is an interspace, which is of a height that is less than the height of the concrete element to be produced. A number of pumps are used, in order to pump concrete into the interspace. The pumps are designed in such a way that the concrete can be introduced at high pressure in such a way that the interspace is filled with concrete and that the concrete element is forced vertically upwards out of the interspace during the hardening of the concrete. As the concrete element rises, an attachments, that later serves for pulling up and mounting various elements, is transported upwards.

This present patent application claims the priority of the PCTapplication PCT/EP 2005/009319, which was filed on Aug. 30, 2005, onbehalf of the above mentioned applicant.

Objects of the invention are a method and a device for verticalextrusion of a concrete element according to the preamble of claim 1 and14 respectively, and a correspondingly produced wind turbine generatortower according to the preamble of claim 22.

The construction of elongated, in vertical direction extending concreteelements is a challenge in different areas of building construction.Among the techniques known so far, one has always proceeded in a similarmanner. To begin the construction work, a foundation is embedded intothe ground. On the foundation, a first construction stage emerges, as acasing is filled with concrete which hardens after a certain time. Afterthe first stage hardens, the casing is removed and fitted at the upperend of the hardened concrete element and is again filled with concrete.This process is repeated until the required height is reached.

To simplify this procedure, so-called climbing or sliding casing isused. Usually one needs at least an auxiliary crane to raise and placeelements again.

The mentioned methods are especially complicated in case of conicaltowers whose diameter decreases at top. Furthermore, the concrete mustbe lifted or pumped to according heights by special devices.

At each construction stage, after the filling of the casing, the workhas to be interrupted until the concrete hardens and the casing can beremoved again.

Another building construction method is that concrete structures arevertically extruded in place in a continuous procedure, as rudimentaryexemplified in the patent specification GB 619048 from 1949. Thisapproach seems not to have proven itself, since for more than 50 years,this issue has not been taken up or further developed.

Another well-known building construction method is that the concreteelements are not cast on location with the aid of casings, but aredelivered precast. Thus a first element will be placed on the foundationcreated earlier. The prefabricated elements are successively stacked upuntil the required height of the structure is reached. Thus, dependingon the size of the elements, complex logistics is required for thetransportation of prefabricated concrete elements. In addition, theelements must be brought to their corresponding place and connectedtogether, partially at extreme heights, with expensive special cranes.

These methods have the disadvantage that they are either relativelycomplicated and expensive, or that they are not applicable in practice,which specially applies to the vertical extrusion process. Especiallyfor wind turbines, this results in a very expensive system, and thus theprice of electricity produced with this system is also relatively high.

Furthermore one should bear in mind that in some areas thetransportation of prefabricated concrete elements is not possible orhardly possible. In such areas wind turbines and other standing verticalconcrete elements have to be constructed conventionally step by stepwith casings.

The present invention is now pursuing the goal of further improving theknown building construction techniques for vertically self extrudingconcrete elements and to significantly reduce the building costs of suchconstructions.

Furthermore, it is an object of the invention to be able to produceparticularly cost-effective wind turbines.

The solution of this problem is provided

-   -   by the process through the features of the characterizing        portion of claim 1;    -   by the device for producing an elongated, in a vertical        direction extruding concrete element through the features of the        characterizing portion of claim 14; and    -   by the wind turbine generating tower itself through the        characterizing portion of claim 22;

The present invention solves the problem in that, for the verticalextrusion of an elongated, itself in a vertical direction extendingconcrete element, an inner and an outer shutter is provided, whereinbetween the inner casing and the outer casing an interspace is made,that has a height which is less than the height of the concrete elementto be produced. In this interspace, at several places of the lower area,concrete will be pumped at high pressure in such a way that theinterspace will be filled with concrete and that, during the hardeningof the concrete, the concrete element will be forced upwards out of theinterspace. Furthermore, an attachment is fitted on the concreteelement, which is transported upwards by the growth of the concreteelement.

This has the advantage that, after a construction stage, one does nothave to wait the hardening of the concrete before the casing can beremoved and newly placed and fitted on the hardened concrete. By pumpingin of the concrete at several places, the concrete element extendingitself in vertical direction can be finished with high quality andstiffness. Furthermore, this has the advantage, that in a certain timemore concrete can be introduced. In addition, the exact vertical growthof the concrete element can optionally be controlled by targeted controlof the concrete flow.

By the use of the attachment, one can dispense with the use of a largecrane or breakdown crane, since the attachment allows all elements,which will be required during or after the construction phase, to becarried up.

According to the invention, the otherwise normal procedural steps aregreatly reduced.

Furthermore, fewer supplies and consumable materials are required at theconstruction site.

Advantageously, fast hardening concrete or concrete with acceleratorwill be deployed. A combination of fast hardening concrete andaccelerator is also possible.

Advantageously, at introduction or before introduction, the concretewill be fitted with enforcement elements, wherein preferably plastic,glass, steel or carbon fiber is used as enforcement element or Monieriron, respectively armored steel is deployed.

This has the advantage that the tensile force sensitive concrete isreinforced. Plastic, glass, steel or carbon fiber enforcement elementscan all absorb tensile forces in the structure and thus provide therequired stiffness.

Advantageously, the concrete element will be seamlessly produced fromconcrete, since its height increases continuously as long as concrete isintroduced at the bottom area of the interspace.

This has the advantage that the work progress does not have to beinterrupted several times. Through the production of the concreteelement “monolithically”, the stiffness of the construction can beadditionally increased.

On the attachment, which is raised to the top by extruding the concreteelement out from the interspace, interior or exterior tensioning meanscan be fitted. Construction components of the concrete element (forexample components of a wind turbine) can be pulled to the top before orafter reaching the end height (H1).

This has the advantage that, during subsequent work stages, a workingplatform is available, with whose help for example the generator housingof a wind turbine can be mounted on the concrete element. Besides,tensioning means can be fixed on the attachment, in order to control thevertical alignment of the concrete element.

Advantageously, the introduction of the concrete and/or the tension onthe tensioning means is controlled so, that the concrete element risesvertically, even if for example wind load acts on the concrete element.

This has the advantage that movements, which the concrete element makesduring the construction phase due to winds for example, can becompensated by selective control of the insertion of concrete and/or byselective control of the tension of the tensioning means.

Preferably, a collar-shaped or belt-shaped element is put around orfitted while pextruding the concrete element out of the interspace.

Advantageously, the inner and/or outer casings can be produced so, thatthe cross-section of the growing concrete element can be changed.

This has the advantage for example, that, due to a lower self-weight,the upper area of the concrete element can be produced with a lower wallstrength. Thus for example, the consumption of materials can be reduced.

It is an advantage of the invention that, through the extrusion,seamless towers, columns, posts or the like with longitudinally constantcross section or with variable cross-section can be produced.

Further advantages arise directly form the description and theassociated drawings.

In the following, the invention will be described in detail by exemplaryembodiments and with reference to the drawings. Which show:

FIG. 1A a first device according to the invention, in a schematic,sectional side view;

FIG. 1B the first device according to the invention, in a schematicsectional view from above;

FIG. 2A a first step of the process according to the invention, in aschematic sectional side view;

FIG. 2B a second step of the process according to the invention;

FIG. 3 a first device according to the invention, for introducing theconcrete at several places with several pumps in a schematic top view;

FIG. 4 a second device according to the invention, for inserting theconcrete at several places with several pumps in a schematic top view;

FIG. 5 an anchorage of the concrete element to the foundation with theaid of anchors in a schematic sectional view;

FIG. 6 the engagement of a fixation element in a cavity in a wall of theconcrete element in a schematic sectional view;

FIG. 7 an anchorage of an attachment on a concrete element, according tothe invention, in a schematic sectional view;

FIG. 8 a schematic sectional view of a growing concrete element withtensioning means and with steering and control means to control thevertical alignment of the concrete element, according to the invention;

FIG. 9 a side view of an extruding tower with a working platform withwhose aid, for example, the generator housing can be mounted on theconcrete element;

FIG. 10 enforcement means which is inserted into a lower part of theinterspace of the casing, in a schematic sectional view;

FIG. 11 an embodiment where a collar or belt shaped ring is put aroundthe extruded concrete element, according to the invention;

FIG. 12 an embodiment of the invention in a top view, where the outercasing has a different cross-section as the inner casing;

FIG. 13A a cross-section through a lower part of a further embodiment ofthe invention;

FIG. 13B a top view of a lower part of the further embodiment of theinvention according to FIG. 13A;

FIG. 14A a cross-section through an outer casing according to a furtherembodiment of the invention;

FIG. 15A a first step of the process of the invention;

FIG. 15B a second step of the process of the invention;

FIG. 15C a third step of the process of the invention.

Constrictive elements with the same function are provided with the samereference sign in all figures.

In the following, the expression extrusion will be used, even though itis unusual in the field of concrete construction. Typically byextrusion, plastics and other semi fluid thermosetting materials arebeing pressed through a nozzle in a continuous process. In addition thismaterial—the extrudate—is being melted and homogenized by heating. Bythe flow through a nozzle, the necessary pressure is provided. Afterpassing through the nozzle, the material solidifies. The cross-sectionof the geometrical piece thus produced is dependent on the nozzle used,or on a calibration placed behind it.

The invention relates to the production on location, of an elongated,itself in a vertical direction extruding concrete element 20. Theinvention is especially suitable for the production of towers (forexample wind generator turbines), poles, masts and pylons (for examplefor bridges or boring platforms). Such a concrete element is produced onlocation, i.e. directly on the destination location. In addition itrequires a special device 10 according to the invention, whose detailsare schematically depicted on FIG. 1A and FIG. 1B, and correspondingequipment. The device 10 comprises an inner casing 12 and an outercasing 11, wherein the inner casing 12 and the outer casing 11 aremanufactured so that there is an interspace 16 between the inner casing12 and the outer casing 11. This interspace 16 is closed on the bottom.On the top end of the casings 11, 12 an exit orifice results.

In the shown embodiment, the casings 11, 12 stand on a foundation 13 ora base. On the foundation 13 or base a foundation step 14 is provided,in order to be able to mount the inner and outer casings 11, 12. Thecasings 11, 12 have a height H, which is less than the height H1 of theconcrete element to be produced. This foundation step 14 is optional,however it provides several advantages, as described in relation to theFIGS. 13A and 15C.

According to the invention, several pumps 17 are provided, in order tobe able to insert concrete 21 with pressure in a lower area of theinterspace 16. It is important, that the pumps 17 are located so thatthe concrete 21 can be inserted with high pressure in such a way thatthe interspace 16 is filled uniformly with concrete 21 from below andthat, during the hardening of the concrete 21, the concrete element 20is pushed (extruded) upwards out of the interspace 16.

Preferably, with regard to the Cariole-force, the concrete is pumped inat an angle, in order to achieve a better homogeneity and to avoid thehardening in the lower filling/pumping area.

Specially preferred are slowly conveying pumps 17 which generate asufficiently high pressure. Spiral pumps are especially suitable.

On FIG. 1A and in FIG. 1B a feed-through element 15 is to be observed,through which the concrete 21 is extracted in the interspace 16. Theextraction direction is indicated by an arrow.

The process of the invention for the vertical extrusion of an elongated,itself in a vertical direction extending concrete element 20 is nowcloser exemplified in relation to the FIGS. 2A and 2B. An inner casing12 and an outer casing 11 are provided on location, i.e. on thedestination location, as already described in relation to the previousfigures. Between these casings 11, 12 there is an interspace 16. Theheight H of the casings 11, 12 is a lot less than the height H1 of theconcrete element 20 to be finished. Typically H is one tenth or smallerthan H1. In certain situations, H can be more than one tenth of H1.

According to the invention, after the construction site is prepared onlocation, the concrete 21 is pumped in a lower area of the interspace16, wherein the concrete 21 is inserted with high pressure. Thus theinterspace 16 is filled from bottom with concrete 21. The top edge 22 ofthe concrete 21 moves upwards as more concrete 21 is pumped from below.The top edge is indicated on the figures with a subsidiary line 22.

While at the bottom concrete 21 is further pumped, at the area of thetop edge 22 the concrete 21 starts to harden. During the hardening ofthe concrete 21, through the pressure of the concrete 21 pumped in theinterspace 16, the concrete element 20 is extruded upwards out of theinterspace 16. In FIG. 2B a snapshot is shown, where a part of thehardened concrete 21 already overtops the casing 11, 12 (i.e. H1>H).

By suitable regulation of the pumping power (or by suitable setting of avalve to be used), the upward shift of the top edge 21 can becoordinated with the hardening of the concrete 21.

Through this vertical extrusion process, the concrete element 20 isseamlessly produced from concrete 21 and its height H1 increases as longas concrete 21 is inserted in the bottom of the interspace 16 withsufficient pressure.

In the following paragraphs further aspects and embodiments of theinvention will be described, wherein the different variants can becombined with each other at will. First of all concepts will beclarified, as long as they require such a clarifying.

The combination of an inner casing 12 and an outer casing 11, accordingto the invention, will be hereinafter indicated as casing. Preferablyflat, spatially curved or bent boards (such as boards, steel plates,plastic plates) are used for molding and bracing. In a speciallypreferred embodiment, a concrete element is used as inner casing, asdescribed later. The casing 11, 12 may comprise pillars or pillarelements. In a preferred embodiment, the inner and/or outer casing isadjustable.

Concrete is an artificial solid body out of cement, concrete aggregate(grained stone) and water. It can further contain additional concreteadditives and concrete admixtures (for example accelerator). The cementacts as binding means in order to keep together the other components.The stiffness of the concrete is caused by hardening (recrystallisation)of the clinker components of the cement, whereby small crystal pins arebeing formed, which firmly interlock with each other. The crystal growthlasts an extended period of time, so that the final stiffness is reachedlong after the extrusion. Through the extrusion process, according tothe invention, a continuous (monoblock) concrete element 20 with a veryhigh quality, homogeneity and stability is built.

Fast hardening concrete or concrete with accelerator is especiallysuitable.

An embodiment of the device 10, that comprises at least one heatingelement, which is placed so that the concrete 21 hardens faster, isespecially preferred. Preferably this ring-shaped heating element sitsat the upper end of the casing 11, 12 or in the inside of a hollow towerto be completed.

Concrete can resist to very high pressure, but it fails even at lowtensile loads. Therefore, the concrete will be preferably provided withMonier iron (reinforcement steel) and/or fitted with enforcementelements (preferably plastic, glass, steel or carbon fiber). Thus, aconcrete element 20 results from bonding construction material, whereinthe concrete, according to its material characteristics, absorbs theforces of pressure and the steel and/or enforcement elements, enclosedby the concrete, absorb the tensile forces.

Specially preferred are warmly formed and ribbed concrete steel bars aswire 32 with suitable diameter and suitable length. During theextrusion, this wire 32 can be inserted from top or bottom into thewalls of the concrete element 20 (also see FIG. 10).

Construction concrete can be used, which can be produced directly on theconstriction site in an own plant or transport concrete can be usedwhich is transported with mixing vehicles from a stationary device andis put for example into a silo 64.

Concrete which has been fitted with enforcement elements is especiallypreferred for the extrusion. For the sake of simplicity, this kind ofconcrete will be called fiberconcrete. The use of enforcement elementsleads to an improvement of the tensile strength, and thus of the breakand crack resistance. Preferably, the fibers will be embedded in theconcrete matrix. They act as a king of armoring.

Long or short tensile load oriented fibers can be used. Fiber mats canalso be used.

Alkali-resistant glass fibers, steel fibers, carbon fiber and plasticfibers (like for example Polyvinylalcohol, Polyethylene, Polypropylene,Kevlar, Polyacrylacid and its slats, Polyacrylate) are especiallypreferred as enforcement elements.

Ideal is concrete with a combination of Monier iron and fiber additives.In an actually preferred embodiment, fiber concrete or syntheticconcrete (concrete with reactive synthetic additives), which isprestressed with steel braids after the extrusion, is being used.

A top view of a device 10 is depicted on FIG. 3, which allows concrete21 to be inserted in a bottom area of the interspace 16 at more than oneplace. In the depicted embodiment, three pumps 17 are provided, eachpumping concrete 21 into the interspace 16 through a correspondingfeed-through element 15. The pumps 17 are preferably controlled so, thatthe vertical rise of the concrete element 20 is controllable.

A top view of a device 10 is depicted on FIG. 4, which allows concrete21 to be inserted in a bottom area of the interspace 16 at more than oneplace. In the depicted embodiment, one pump 17 is provided that pumpsconcrete in a distributing ring 18. The distributing ring 18 isconnected by radially oriented bar-pipes with the feed-through elements15, so that each will pump concrete 21 in the interspace 16. Adjustablevalves are preferably fitted in the areas of the bar-pipes, which can becontrolled so that the vertical rise of the concrete element iscontrollable. It is to be noticed, that the distributing ring 18 and theother elements of the drawing are pictured in a very schematically.

Other assemblies are also conceivable in order to ensure the uniforminsertion of concrete. Adjustable assemblies are preferred.

As described in relation to the preceding embodiments, a foundation 13or a foundation step 14 is provided at the destination place. This canbe done in the usual way. A foundation 13 or a foundation step 14 withmeans (for example ring-shaped step 14) for fitting the casings 11, 12is preferred.

In order to ensure a statically stable connection between the foundation13 and the extruding concrete element 20, Monier iron bars arepreferably inserted. On FIG. 5, a cross section of a concrete element 20is shown that rests on a foundation 13. Tie bars 19 are molded in thefoundation 13, which comprise an anchor, which extends in a verticallyupward direction. By the insertion of the concrete 21 in the interspace16 between the casings 11, 12, this anchor 19 will be surrounded byconcrete. After the hardening of the concrete, a deep connection resultsbetween the concrete element 20 and the foundation.

There are other possibilities to connect the concrete element 20 withthe foundation 13. For example, an embodiment is depicted on FIG. 6, bywhich an anchor 19 is provided with an opening or an ear at the upperend. A vertically upwards extending channel 23 is provided in the wallof the concrete element 20. A steel element (a steel cord 30 forexample) runs through this channel 23, which stays under tension or isput under tension (pretension) after the extrusion.

The concrete element 20 comprises respectively an attachment 24. Thisattachment 24 is preferably mounted from beginning on the raisingconcrete element 20 and step by step it will be moved upwards as theconcrete element 20 rises. Thus cranes and other lifting means aredispensable.

The attachment 24 can overtake one or more of the following functions:

-   -   it can act as fixation for the tensioning means 31,    -   it can comprise a lifting tool 31, 32, 33 in order to be able to        lift up construction parts during or after the finishing of the        concrete element 20,    -   it can act as a mounting platform for construction parts.

On FIG. 7, the upper end of a concrete element 20 is shown. Anattachment 24 sits on the top edge 22 of the concrete wall 21. The shownattachment 24 comprises ring-shaped inner and outer collars, in order toensure a secure hold on the concrete wall 21. As schematically shown onFIG. 7, anchors 19 can be used at the upper end of the concrete element20.

The functioning principle of the tensioning means 31 will now beclarified in connection with FIG. 8. A tower 20 during the extrusion isshown on FIG. 8. The tower 20 comprises an attachment 24. Three steelcords 25 (preferably very hard cords are being used) are fixed to theattachment 24, in order to stabilize in the tower 20 in relation to thevertical direction according to the triangulation principle. This isimportant, since the tower 20 rises in vertical direction through thepumping in of concrete and is eventually labile or slightly instable.Preferably, during the extrusion it is determined whether the tower isvertical. That can be achieved with a perpendicular or a similarmeasuring device. In FIG. 8, a light- or laser beam 27 is used as anelectro-optic measuring device, which is emitted parallel to alongitudinal axis of the tower by a transmitting/receiving device 26 andreflected on the attachment 24. Such a transmitting/receiving device 26reacts very sensitively to the smallest deviation from the verticaldirection. A control circuit can be constructed, which makes possible,with the use of electronically driven cable winches, the individualadjustment of the tension of the cords 25. The control circuit shouldpreferably be designed so that during the extrusion of the concreteelement 20, the steel cord 25 is slowly but continuously unwounded.Specially preferred are tensioning means, which make possible to ensurethat the compression load in the wall 21 of the tower is alwaysapproximately the same. With growing height H1 of the top edge 22 of thetower 20, the cord tension can be reduced since the self weight of thewall 21 exercises increasing pressure on the concrete in the interspace16.

The tensioning means are preferably tensioned with hydraulic pumps (ascord lifting equipment).

In the lower part of FIG. 8, a regulating and control means 40 is shownin a very simplified from, which receives signals through a link 41 fromthe transmitting/receiving device 26 and controls the cable winchesaccordingly, as hinted by the links 42.

The way the attachment can act as lifting equipment is now elucidated inconnection with FIG. 9. In FIG. 9, the tower 20 of a wind turbinegenerator is shown after extrusion. Lifting means are provided on theattachment 24. In the present case, lifting means is about a (steel)scaffold 36, a cable winch 33 (it can be about a diverter roller in casea cable winch is provided on the ground) and a weight lifting cord 31.Thus one can raise upwards construction parts without a crane or otherlifting equipment.

The lifting means can be left on the tower, so that at a later point intime it can be used for maintenance.

It is also conceivable, that a cable winch stands on the ground, andconstruction parts are raised above by that the weight lifting cord runsaround one or more rolls of a pulley. These rolls can be found in thiscase on the attachment 24.

A basic condition that must be fulfilled, in order for the method of theinvention to function, is that the pressure of the pumps 17 has to besufficient, so that on one hand to fill the interspace 16 of the casing11, 12 and on the other hand to push upwards the emerging concreteelement 20 together with possible additions or superstructures.

The practicability of the invention will be elucidated by reference tothe following example. A tower 20 is to be produced, which has an innerdiameter D1 of 2.5 m, an outer diameter of 2.8 m and a height H1 of 45m. Concrete with a specific weight of 2.5 t/m³ is being used. Henceresults a weight of approx. 150 t of the tower (without additions orsuperstructures). The weight of additions or superstructures (forexample generator, generator housing, wind turbine, etc.) ads up to 40t. Hence results a complete weight of 190 t. That exercises a pressureof approx. 16 bar in a lower part of the casing 11, 12. Bearing in mindfriction losses and other factors, at pumping, a pressure of 18.5 barsmust be provided. When the pump(s) have an aggregate flow rate of 1m³/h, then it lasts between 50 and 60 hours until the tower 20 iscompletely extruded.

This example shows that the necessary pressure and flow rate can beachieved with appropriate pumps 17.

During the extrusion, vertically running channels (e.g. channel 23) orother specially formed areas can be provided. For example, the channelscan accommodate cables, steel cords, ladders or the like.

As hinted, a longitudinal armoring can be introduced from bottom or top.On FIG. 10 the introduction from below is presented. Adjacent to theconcrete element 20 to be produced, a roll 34, with monier iron (e.g.wire) wound up on it, is provided. This wire 32 will be inserted in theinterspace 16 preferably through a duct in the outer casing 11. In orderto avoid concrete to exit, seal lips 35 or the like can be provided. Bythe hardening of the concrete 21, the wire 32 will be anchored stronglyin the concrete element 20 and through the upwards oriented movement ofthe concrete element 20, monier iron will be step by step unwound fromthe roll 34.

In FIG. 11 it is schematically implied, that around the raising concreteelement 20 collar or belt-like elements 29 can be laid. Such elements 29are specially preferred when the concrete element 20 is exposed tostrong pressure loads. For example, this way the earthquake protectionof bridge pylons can be improved.

In order to be able to provide optimal environmental conditions for thehardening of the concrete, in a preferred embodiment, the rising toweris surrounded outside and/or inside with a tubular shell (e.g. a shellmade out of plastic foil). This shell can be unrolled from a roll duringthe extrusion of the tower and pulled with it upwards. By such a shell,the air humidity can be kept over several days in the area between 90and 100%. Eventually a heater/air humidifier can be used in the interiorof the tower. The shell can be simply removed later.

It is obvious, that the concrete element 20 can also have other crosssections and before all can also different cross section by height.

On FIG. 12 a concrete element with a different cross section is shown. Aring-shaped casing element acts as inner casing 12. The outer casing 11has the form of a polygon (in the shown example an octagon). Through theradial shifting of the individual casing walls of the outer casing 11,the thickness of the concrete element can be varied during theextrusion.

Especially preferred is an outer and/or inner casing of a large numberof single, elongated stripes, which are arranged side by side in theshape of a polygon. The diameter of the casing can be increased byinserting more stripes. A reduction is possible in that one removesstripes.

In the FIGS. 13A and 13B details of a further embodiment are shown. OnFIG. 13A it is to be noticed, that a foundation is provided in theground. A foundation step 14 of concrete will be cast on thisfoundation. A door 60 can be provided in this foundation step, whichallows an inner entry. Either can now the inner and outer casings bemounted on the foundation step as shown in FIG. 1A or a further casing61 can be cast as integral part of the foundation step 14. This latestversion is shown on FIG. 13A and FIG. 13B. The foundation step 12 has aheight HS and the inner concrete casing 61 has a height HI. The outercasing 11 is indicated on FIG. 13A only with lines. Between the outercasing 11 and the inner casing 61 an interspace 16 is given, which willbe filled with concrete from several places in the bottom. In thefoundation 13 and foundation step 14 different anchors 19 or Monier ironrods are provided.

In the FIGS. 14A and 14B details of an outer casing 11 are shown. Theouter casing comprises three cross segments, which each cover 120degrees. The three elements are connected by means of flanges 63 andthen form a cylindrical inner space with a diameter Da. In the shownexample, inlets 15 for connecting the pumps are provided in threeplaces. In order for the casing to be lifted, hooks or ears can befitted for example.

In the FIGS. 15A to 15C details of a further method according to theinvention are shown. In FIG. 15A a construction phase is shown,according to which the foundation step 14 together with the concreteinner casing 61 is being produced. In the foundation step 14, a dooropening 60 is provided. Now an outer casing (for example the one shownin FIG. 14A) is mounted and concrete will be introduced in theinterspace 16 from a silo 64 by pumps 17 through inlets 15. The concreteelement rises upwards, as shown in FIG. 15B, and thus carries theattachment 24. Steel scaffold 36 with lifting equipment and the like arefitted on the attachment. In the inside of the tower electro-opticalmeans 26 (as already described) are placed, so that, during the risingof the tower, the vertical alignment can be checked and corrected.

On FIG. 15C, a few finishing steps are described. A cable channel 23 islaid in the foundation, so that the tower can be conducted with a cable66. In the inside of the tower, an elevator cabin 65 or a liftingplatform is provided. On the attachment 24, measuring constructions 67for measuring the wind speed and weather conditions as well as thegondola 50 of a wind turbine are mounted.

1. Method for vertically extruding an elongated, itself in a vertical direction extending, cylinder shaped concrete element (20), with the following steps: providing an inner casing (12), providing an outer casing (11), wherein between the inner casing (12) and the outer casing (11) an interspace (16) is formed, which has a height (H), that is less than the height (H1) of the concrete element (20) to be finished, introducing the concrete (21) in a lower area of the interspace (16), wherein the concrete (21) is inserted with high pressure so that the interspace (16) is filled with concrete (21) and that during the hardening of the concrete (21), the concrete element (20) is being extruded vertically upwards out of the interspace (16) characterized in that the concrete (21) is introduced in more than one place in the lower part of the interspace (16) and that on the concrete element (20) in an upper part an attachment (24) is placed, which is being raised upwards by the pushing out of the interspace (16) of the concrete element (20).
 2. The method according to claim 1, characterized in that during the introduction or before the introduction, the concrete (21) is provided with enforcement elements, wherein preferably synthetic, glass-steel, or carbon fiber are used as enforcement elements.
 3. The method according to claim 1, characterized in that the concrete element (20) is produced seamlessly from the concrete (21) and its height (H1) increases as long as concrete (21) is introduced in the lower part of the interspace (16).
 4. The method according to claim 1, characterized in that internally or externally running tensioning means (25, 28) are fitted on the attachment (24), wherein a preferably triangular arrangement of tensioning cords (25) acts as tensioning means.
 5. The method according to claim 4, characterized in that, during the extrusion out of the interspace (16), the vertical alignment of the concrete element (20) is controlled through controlled tensioning of the tensioning means (25, 28).
 6. The method according to claim 1, characterized in that the means (28, 31) are fitted on the attachment (24), so that, after achieving the height (H1) of the concrete element (20) to be produced, construction parts can be pulled upwards.
 7. The method according to claim 1, characterized in that, means are fitted on the attachment (24) so that construction parts can be fitted.
 8. The method according to claim 1, characterized in that the introduction of concrete (21) is controlled so that the concrete element (20) rises vertically.
 9. The method according to claim 1, characterized in that the inner and/or outer casing (11, 12) is made so that the cross section of the rising concrete element (20) can be changed.
 10. The method according to claim 1, characterized in that, in a preparing step, a foundation of concrete is provided, which is either arranged so that the inner casing (12) and the outer casing (11) can be fixed on this foundation, or arranged so that an integral part of the foundation acts as inner casing (12) and only the outer casing (11) must be fixed on this foundation.
 11. The method according to claim 4, characterized in that an electro-optical measuring device is used during the vertical extrusion, so that a deviation form the vertical direction can be detected, and thus, during the vertical extrusion, by means of the tensioning means (25, 28) a corresponding correction is conducted.
 12. The method according to claim 1, characterized in that during or after the vertical extrusion: outside on the cylindrical concrete element (20) a temporary shell, preferably a tubular shell is fitted, and/or inside in the cylindrical concrete element (20) a temporary shell, preferably a tubular shell is fitted, so that suitable environmental conditions are provided for the hardening of the concrete.
 13. The method according to claim 4, characterized in that the temporary shell(s) will be pulled from the ground during the extrusion.
 14. Device for producing on location of an elongated, itself in a vertical direction extending concrete element (20), with with an inner casing (12), an outer casing (12), wherein the inner casing (12) and the outer casing (11) are made so that between the inner casing (12) and the outer casing (11) there is an interspace (16), which has a height (H), that is less than the height (H1) of the concrete element (20) to be finished, characterized in that several pumps (17) are provided for the introduction of the concrete (21) in more than one place in lower areas of the interspace (16), the pumps (17) are placed so that the concrete (21) can be introduced with high pressure in such a way that the interspace (16) is filled with concrete (21) and that, during the hardening of the concrete (21), the concrete element (20) is extruded out of the interspace (16) vertically upwards, and that on the concrete element (20), in an upper area, an attachment (24) is fitted, which is being raised upwards by the pushing out of the interspace (16) of the concrete element (20).
 15. The device according to claim 14, characterized in that means (15, 17, 18) are provided, so that the concrete (21) can be introduced in more than one place in the bottom part of the interspace (16), wherein preferably a centering means is used, so that the pressure in the bottom part of the interspace (16) can be controlled, that rises the concrete element (20) vertically.
 16. The device according to claim 14, characterized in that means are provided so that during the introduction or before the introduction, the concrete (21) can be provided with enforcement elements, wherein preferably synthetic, glass-steel, or carbon fiber are used as enforcement elements.
 17. The device according to claim 16, characterized in that the means (34, 35) are placed so, that iron bars or wire (32) as Monier-steel is inserted from below in the interspace (16) and will be shifted upwards with the concrete element (20).
 18. The device according to claim 14, characterized in that the inner casing (12) and the outer casing (11) are made so that they can be connected with a foundation (13, 14) on which the concrete element (20) is to be produced, whereby the inner casing (12) and the outer casing (11) are tightly connected to the foundation (13, 14).
 19. The device according to claim 14, characterized in that it comprises a concrete foundation, which features a cylindrical concrete wall, which acts as inner casing, and that the outer casing (11) is made so that it is connected with the concrete foundation, wherein the outer casing (12) is connected tightly with the foundation.
 20. The device according to claim 14, characterized in that the device comprises a control (40) and tensioning means (25, 28) are provided on the attachment (24), wherein, during the extrusion out of the interspace (16), through controlled tensioning of the tensioning means (25, 28), the vertical alignment of the concrete element (20) can be controlled by means of the control (40), wherein tensioning means (25, 28) relate to inner and/or outer tension cords.
 21. The device according to claim 14, characterized in that the device comprises a temporary inner and/or outer shell, preferably a tubular shell.
 22. Wind turbine generator tower with an elongated, itself in a vertical direction extending, concrete element (20), is extruded vertically in a continuous extrusion process from between an inner and an outer casing (11, 12), wherein the concrete element comprises an attachment (24), which during the extrusion process acts for the tensioning of the concrete element (20) and after the hardening of the concrete element (20) is suitable as lifting means (31,33, 36) for construction elements (50) of the wind generating turbine, which are to be fixed on or to the concrete element (20).
 23. Wind turbine generator tower according to claim 22, characterized in that it has a homogeneous composition through recrystallizing of clinker components of the cement used as part of the concrete (21).
 24. Wind turbine generator tower according to claim 22, characterized in that construction parts (50) of the wind turbine generator, like a gondola, a generator, or wind sails for example, can be lifted to the upper end of the concrete element (20) with the lifting means (31, 33, 36). 